In the early days of the Syrian rebellion, it was widely assumed that the Assad dictatorship would collapse in short order. The “Arab Spring” had already cast off tyrannies in Tunisia and Egypt. The Ghaddafi regime in Libya would soon join that list. The decline in oil prices was putting pressure on the petrol economies of Syria’s chief patrons, Iran and Russia. The president of the United States indicated that it was time for Assad to go. Most important, a broad swath of Syrian society had initiated peaceful pro-democracy protests, from Damascus to Aleppo. When the Assad regime responded with lethal violence, the opposition took up arms against the state.

Yet, despite predictions, Assad has clung to power using a potent combination of savagery and cunning. From the start, al-Assad brutally repressed the citizenry and relentlessly deployed state propaganda to paint the rebels as a motley crew of jihadists and terrorists. In time, the secular and nationalist factions of the Syrian opposition did in fact lose ground to the Islamist radicals of ISIS and the Nusra Front.

There is compelling evidence that the Syrian government forged a tacit non-aggression pact with the Islamists in order to concentrate its firepower against the more sympathetic and secular Free Syrian Army. Such an alliance would represent a continuation of policy, given that Damascus labored mightily to foment jihad in Iraq under the U.S. occupation. What’s more, at a critical point in the struggle, the world’s powers withheld significant material aid from the secular opposition. By contrast, the jihadist gangs received ample support from their anti-Assad patrons.

In the most recent phase of the conflict, however, the regime has suffered major battlefield reverses, despite the efforts of Iran and its proxy, Hezbollah. Although it retains key strongholds in Damascus and along the corridor to the sea, the regime's army has, for the first time, ceded precious territory in the western region of the country. Tehran will never forsake al-Assad, but Moscow seems to be turning in that direction. It is no wonder speculation has returned about the impending fall of the House of Assad. Such an outcome certainly cannot be ruled out, which raises the question: Which forces stand to gain most in a post-Assad Syria?

If the regime falls, the fighting forces who inflicted the defeat will fill the void and dictate the ensuing political and social environment. This will surely not be the Kurds, whose power is confined to Syria’s northern extremity and have no additional territorial ambitions. Nor will it be the secular rebels – outnumbered and outgunned – who have begun to abandon the battlefield and are only now beginning to receive training and equipment. It is the jihadist armies that are clearly ascendant. The province of Idlib has almost entirely fallen to a Salafi coalition known as Jaish al-Fatah, or the Army of Conquest, which includes al-Qaeda offshoots Ahrar al Sham and the Nusra Front.

But it is ISIS that stands at the vanguard of the Syrian jihadists, controlling fully half of Syria. Across the Iraqi frontier, ISIS has held its own against the central government in Baghdad, U.S. airstrikes and Iranian-backed Shiite militias. But in Syria it has flourished, showing huge reserve strength by taking the ancient city of Palmyra, marching to the outskirts of Aleppo and holding its position within striking distance of Damascus. If al-Assad loses his grip on power, the smart money is on the army of terror inheriting the bulk of what remains of Syria.

It seems equally clear who will not benefit in a post-Assad Syria: namely, the majority of Syrians, whose desire for democracy triggered al-Assad’s murderous response. The fact that specific groups – the Alawites, along with other religious minorities – will fare especially poorly under the caliphate is not reason to exculpate the Assad regime of its many sins. It should not be forgotten that one of those sins was the regime’s determined cultivation of the menaces like ISIS that now threaten to consume it.